chouw@buster.cps.msu.edu (Wen Hwa Chou) (11/28/90)
Hello, here is a real interesting case for NeXT. I received the report that one of our NeXT is disk full. So I went out and checked it. But the total number I've got for all the local files is always 200MB less than the disk space. So where did the 200MB go? I went on checking the process table. They are all friendlies. No bad guys. However, two of the process looked strange enough. It is a pair of csh and mail processes. I cannot find anything funny of those two processes untill I check where did that user from. The answer is: ttyp2 of that NeXT. What make this so special is there is no body login from console of that machine at that time. I myself and that user are the only guys on that system. So how the hell could those processes be there? Again, the total space used by all the processes are only 40M also. We still come out 160MB short. Since the that orphant tty session have been idled for 11 hours. I decided to kill them. Once I did that, boom! All the missing 200MB came back! Gosh, could anyone of you who can make a reasonable explain of this for me. -- Wen
mouse@thunder.mcrcim.mcgill.edu (der Mouse) (11/30/90)
In article <1990Nov28.080352.23755@msuinfo.cl.msu.edu>, chouw@buster.cps.msu.edu (Wen Hwa Chou) writes: > Hello, here is a real interesting case for NeXT. > I received the report that one of our NeXT is disk full. So I went > out and checked it. But the total number I've got for all the local > files is always 200MB less than the disk space. So where did the > 200MB go? > [...runaway csh and mail, corresponding to someone who has already > logged out...] > Again, the total space used by all the processes are only 40M also. > We still come out 160MB short. Since the that orphant tty session > have been idled for 11 hours. I decided to kill them. Once I did > that, boom! All the missing 200MB came back! Once a file is open, it remains in existence until it is closed. (If it has any names in the filesystem, it sticks around until they're gone too.) So either the csh or the mail - or both - presumably had a file somewhere open, but all its names in the filesystem had been deleted. When you killed the processes, this reference to the file went away and it was deleted, thus freeing the space it was occupying. This is not NeXT-specific; all UNIX variants I know of behave this way. I suspect everything since V7 has. der Mouse old: mcgill-vision!mouse new: mouse@larry.mcrcim.mcgill.edu